Conventionally, waste heat energy released from a factory, an incineration facility, or the like is recovered so as to perform electric power generation. The electric energy obtained from the electric power generation is reused, and thereby energy saving is advanced. In such a factory or a facility, the waste heat of about 300° C. or more (near 1000° C. in some cases) is used for the electric power generation, because high-pressure steam used to drive a power generator can be easily produced. On the other hand, much of the low-temperature waste heat of about 300° C. or less is still released into the atmosphere. Therefore, if the waste heat energy of the low-temperature waste heat which is not recovered in most cases in the related art is recovered to perform the electric power generation, a further energy reduction may be achieved.
Patent Document 1 shown below discloses a waste heat power generator which generates electric power using the waste heat energy of the low-temperature waste heat of about 300° C. or less by a Rankine cycle using a low-boiling working medium. Patent Document 2 shown below discloses a technology in which in a waste heat power generator using a Rankine cycle, part of liquid condensate of a working medium is guided to a cooler of a generator, to cool the generator using the evaporative latent heat of the working medium.